The present invention relates to apparatus for manufacturing large-surface, tape-shaped silicon bodies for solar cells by means of coating a carrier body with molten silicon, said carrier body being resistant to the silicon melt but being moistenable by the melt and exhibiting a mesh structure, wherein a melt vat accepting the silicon melt and guide devices in the area thereof are provided, these ensuring that the carrier body to be coated is continuously brought into contact with the melt.
Such a device can be derived from the German OS No. 28 50 805. A carrier body comprised of a graphite mesh is thereby drawn tangentially across the surface of the silicon melt situated in the melt vat in a continuous method, whereby the carrier body is incorporated in the silicon tape after the crystallization process. A surface drawing rate of one meter squared per minute (1 m.sup.2 /min) can be achieved with this method.
The convection currents occurring in the melt in the prior system present technical difficulties, these leading to considerable temperature fluctuations at the crystallization front and, thus, to fluctuations in the thickness of the silicon layer. It is also difficult to continuously and uniformly re-supply the silicon melt and, thus, to always keep the melt level at the same height, this likewise being a necessary precondition for a uniform coating of the carrier body.
A more uniform coating is achieved when, as disclosed in the German OS No. 30 10 557 Al, the coating is supplied relative to the drawing rate such that only a thin layer is formed in the meshes of the carrier body net comprised of graphite or graphitized silica glass threads due to the high surface tension of the molten silicon and the fact that the tape-shaped net is guided through a slit-shaped opening of a channel applied in the floor part of the melt vat and extending in the direction toward the melt surface, whereby the slit-like opening is matched to the dimensions of the tape-shaped net (thread thickness). The problem of re-supplying silicon into the melt vat is not yet satisfactorily resolved here.